Problems such as a long delay and low bandwidth of electrical interconnection always restrict development of the fields such as computers and integrated circuits. In recent years, these problems gradually become a bottleneck for rapid development of these fields. Optical interconnection has a tendency to replace the electrical interconnection because of advantages in speed, bandwidth, power consumption, costs, and the like.
However, the optical interconnection technology is not mature yet and has many to-be-resolved problems, for example, thermal noise of a photoelectric detector. As speed increases, a carrier in a modulator of an optical transmitter module cannot move fast enough, and as a result, an extinction ratio (this means, a ratio of optical signal power existing when an optical signal is 1 to optical signal power existing when the optical signal is 0, a greater extinction ratio indicates better signal quality) of an output optical signal is decreased, causing an increase in a bit error rate and finally affecting normal operation of a system.
In the prior art, a common method for resolving the foregoing problem is to add a signal driver module for an input electrical signal, so as to increase a voltage of the electrical signal input into an optical modulator. According to the foregoing method, an extinction ratio of an output optical signal is increased to some degree, and a relatively easily recognizable optical signal is obtained.
The inventor finds, through research on the foregoing implementation solution in the prior art, that the foregoing implementation manner has the following problems.
To increase a voltage of an electrical signal input into an optical modulator, a size of a drive circuit needs to be increased, which not only increases the difficulty in designing the drive circuit but also greatly increases power consumption of conversion from an electrical signal to an optical signal. In addition, the increase in the voltage of the electrical signal also causes an increase in electromagnetic radiation, causing more system noise, and causing much interference to the optical signal during a transmission process.